Variability of Extended Bipolar Regions

Using NSO/Kitt Peak synoptic charts from 1975 to 2003, we group the main solar magnetic fields into two categories: one for active regions (ARs) and the other for extended bipolar regions (EBRs). Comparing them, we find that there exist three typical characteristics in the variability of EBRs: First, there exists a correlation between ARs and EBRs. The phase of EBR flux has a delay nearly two CRs. Second, we find that the EBR flux has two prominent periods at 1.79 years and 3.21 years. The 1.79-year period seems to only belong to large-scale magnetic features. Lastly, the North – South asymmetry of EBR flux is not very significant on a time scale of one solar cycle. However, during solar maxima, its dominance is found to shift from one hemisphere to the other.     

胶东牟平—乳山地区花岗岩副矿物特征及其成因

本文论述了牟平—乳山地区花岗岩的岩石学特征,副矿物组合特征,尤其是锆石特征,副矿物的化学成分与微量元素及稀土元素组合特征,并在此基础上探讨了花岗岩的成因。本区花岗岩的成因是复杂的,既有花岗岩化作用(交代作用)和深熔作用形成的花岗岩,又有岩浆分异结晶作用的产物。     

Lead in corals: reconstruction of historical industrial fluxes to the surface ocean

Twentieth century environmental lead chronologies for the western North Atlantic, Pacific, and Indian Oceans have been reconstructed from annually-banded scleractinian corals. Measurements of lattice-bound Pb in sequential coral bands reveal temporal changes in surface water Pb concentrations and Pb isotopic distributions. Perturbations are observable in all specimens studied, attesting to global augmentation of environmental Pb by industrialization.In the western North Atlantic, Pb perturbations have occurred in direct response to the American industrial revolution and the subsequent introduction and phasing-out of alkyl Pb additives in gasoline. Surface ocean conditions near Bermuda may be reliably reconstructed from the coral data via a lead distribution coefficient of 2.3 for the species,Diploria strigosa. Based on²¹⁰Pb measurements, a similar distribution coefficient may be characteristic of corals in general. Surface Pb concentrations in the pre-industrial Sargasso Sea were about 15–20 pM. Concentrations rose to near 90 pM by 1923 as a result of metals manufacture and fossil fuel combustion. Beginning in the late 1940's, increased utilization of leaded gasoline eventually led to a peak concentration of 240 pM in 1971, representing an approximate 15-fold increase over background. Surface ocean concentrations are presently declining rapidly (128 pM in 1984) as a result of curtailed alkyl Pb usage. Lead isotopic shifts parallel the concentration record indicating that characteristic industrial and alkyl Pb source signatures have not changed appreciably in time. Industrial releases recorded in the Florida Keys reflect a weaker source and evidence of recirculated Pb (5–6 years old) from the North Atlantic subtropical gyre. An inferred background concentration of 38 pM suggests influence of shelf and/or resuspended inputs of Pb to these coastal waters.In remote areas of the South Pacific and Indian Oceans, industrial signals are fainter and the corals studied much younger than their Atlantic counterparts. Contemporary Pb concentrations implied by coral measurements (assumingK_D = 2.3) are 40–50 pM for surface waters near Tutuila and Galapagos in the South Pacific, and 25–29 pM near Mauritius in the Indian Ocean. A single coral band from Fiji (1920 ± 5yr) implies a pre-industrial surface water concentration of 16–19 pM Pb for the South Pacific. In view of reported surface water measurements and the North Atlantic coral data, the Pacific coral extrapolations may be slightly high. This could be a result of small variations inK_D among different coral genera, or incorporation of diagenetic Pb by corals sampled in coastal environments.     

Sr,Nd and O Isotopic Studies on the Genesis of the Huashan Granite Complex1

Abstract Systematical Sr, Nd and O isotopic studies were made on the Huashan granite complex in Guangxi. In combination with the studies of geological, petrological and geochemical data, it is believed that the complex consists of granites of three stages, with different geneses and different source materials. They are not the products of differentiation and evolution of one single consanguineous magma. Granites of the 1st stage are of the Indosinian syntectic type or I type, also derived from a mixed mantle-crustal source. Those of the 2nd stage are of the early Yanshanian syntectic type or I type, also derived from a mixed mantle-crustal source, and those of the 3rd stage are of the late Yanshanian transformed type or S type, derived from a crustal source.     

二维任意倾斜地层的层速度计算结果分析

本文主要介绍沙赫(Shan,P.M.)公式,对二维任意倾斜地层的层速度计算的应用效果。依据实际地层剖面Φ、V、Z参数的可能变化,设计18个较为复杂的地层模型进行了大量试算,并与Dix公式计算结果作了对比,表明对任意倾斜地层应采用沙赫公式提取层速度才是适宜的。     

深海底リアルタイム観測ネットワークの構築

近年来,我国地震观测取得了长足进展,同时海底观测系统的建设也方兴未艾。而欧美及日本等发达国家在海底有线实时监测的成功先例,为我国相应工作的开展提供了良好的参考及借鉴。其中日本海底有线实时监测系统DONET始建于2011年,专注于海底地动—水压信号的高效采集,旨在监视日本南海海槽的地震和海啸事件。本文主要介绍DONET的硬件布局、搭建流程以及科研产出情况,并简要介绍我国国家海底科学观测网的基本信息。     

西南大面积低温成矿域：研究意义、历史及新进展

我国西南大面积低温成矿域是目前世界上公认的2个大面积低温成矿域之一,其面积之大（约100万km^2）、包含的矿种之多（Au、Hg、sb、As、P、Pb—Zn、Ag以及萤石、冰洲石、水晶、分散元素等）、矿床组成和组合之复杂全球罕见,是我国重要的Au、Hg、sb、As、Pb—zn、Ag以及多种分散元素生产基地。国内外学者对该成矿域进行了近30年的研究工作,取得了大量高水平研究成果,同时也存在许多有待深人研究的科学问题。本文回顾了我国西南大面积低温成矿域的研究历史,总结了各研究阶段的主要研究内容、主要研究成果和存在的主要科学问题,同时介绍了近年来我国西南大面积低温成矿域研究新进展。     

洞庭湖退田还湖及其生态恢复过程分析

洞庭湖曾是我国第一大淡水湖泊,盛期面积达6000km2以上,具有调蓄长江中游洪水的巨大生态服务功能.但经过近百年来的沧桑变迁,湖泊发生了巨大变化,由于泥沙的严重淤积和围湖垦殖活动,湖泊面积已萎缩至2625km2,为我国第二大淡水湖泊.湖泊萎缩削弱了其生态服务功能,并由此引发了江湖洪水愈演愈烈的形势.1998年长江流域洪涝灾害之后,中国政府及时提出了"退田还湖"等洪水治理的32字指导原则,湖区各地随即积极开展了"退田还湖、平垸行洪和移民建镇"等工程.本文针对湖区退田还湖双退堤垸的生态恢复过程,选择湖南省汉寿县的青山垸进行了跟踪研究.结果显示了湖泊湿地恢复的阶段性特征,并为我国日益严重的湖泊富营养化问题的治理,提供了新的途径和可供参考的科学依据.